With the development of mobile phone technologies and the improvement of people's material life, people have demanding requirements on multimedia experience of a mobile phone, and a camera has become a mandatory function for a mid-to-high end mobile phone, in which the multimedia refers to that the technology enables a mobile phone user to obtain, process, edit, store, and display two or more than two different types of information media. In the photographic function of the mobile phone, to improve the photograph experience, a flash lamp function is integrated in the camera. This enables the mobile phone user to take a picture with better quality by increasing the exposure by using the flash lamp when ambient light is comparatively dim.
The work procedure of a camera's flash lamp in the prior art includes two steps: fire a pre-flash and a flash. Firing a pre-flash refers to that a dim light is sent out for a photographed person to adjust pupils to the light before the flash lamp is enabled. Then, the camera flashes to reduce influence of darkness and backlight on automatic focusing of the camera and to enable the photographed person to adjust the pupils to prevent a residual phenomenon due to the flashes entering the pupils of the photographed person when the surrounding is relatively dark, which prevents a red-eye problem.
However, during the process of controlling the flash where the prior art is used, flash intensity of the flash lamp when it flashes is fixed, which inevitably leads to a result that the picture that is taken is underexposed because the surrounding is too dark or the picture that is taken is overexposed because the surrounding is not so dark. As a result, the picture that is taken is of poor quality and unsatisfying effect.